The present invention relates to methods, apparatus and systems for generating and delivering high power laser energy to perform laser operations, including drilling, welding, cutting and cladding operations. In a particular, an embodiment of the present invention relates to generating and providing high power laser energy, down hole, to provide laser energy for performing laser operations in a borehole.
As used herein, unless specified otherwise “high power laser energy” means a laser beam having at least about 1 kW (kilowatt) of power. As used herein, unless specified otherwise “great distances” means at least about 500 m (meter). As used herein, unless specified otherwise, the term “substantial loss of power,” “substantial power loss” and similar such phrases, mean a loss of power of more than about 3.0 dB/km (decibel/kilometer) for a selected wavelength. As used herein the term “substantial power transmission” means at least about 50% transmittance.
As used herei the term “very high brightness laser” should be given its broadest possible meaning, unless specifically stated otherwise, and would include laser beams having an M2 of 2 or less, a beam parameter product (BPP) of 50 mm mrad (millirad) or less, and laser beams having both of these properties, as well as the lasers that produce such laser beams.
Generally, the term “about” as used herein unless specified otherwise is meant to encompass a variance or range of ±10%, the experimental or instrument error associated with obtaining the stated value, and preferably the larger of these.
As used herein, unless specified otherwise, the terms “at least ——————” or “greater than ——————” means the same thing as “not having lower than ——————” or “excluding lower than ——————” or “not having less than ——————” or “excluding less than ——————.” Thus, the term “at least 10 kW” is the same as, and means the same thing as, the terms “not having a power lower than 10 kW” or “not having a power less than 10 kW”. Similarly, the term “greater than 10 kW” means the same thing as the terms “excluding a power lower than 10 kW” or “excluding a power less than 10 kW.”